# statistics

1. ### Questions on the Fundamentals for Various Sampling Methods

Hello, I've recently been studying various sampling methods, specifically SRS (Simple Random Sampling), Stratified Sampling, Ratio/Regression Estimation, and Cluster Sampling. I wanted to ask a few questions regarding these methods to better understand the pros and cons for each of them and when...
2. ### Stastical analysis in agronomy and agriculture

Hello all members, I need your guidance about the analysis, as you are good at statistics. I explain my experimental design. Actually I inoculated 3 microorganisms (ASS-ASL and ASY using different concentrations i.e. 50-75 and 100ul/L). I wanted to check if these organisms at different...
3. ### Solving an autoregressive equation

Hi, has anyone an idea how to solve this equation: y_t - y_t-1 = c + delta*t + phi*y_t-1 + eps_t I would be super grateful if anyone could help. Cheers!
4. ### ANCOVA Table - Interpretation

Hello, I don't know if there is any post already regarding this and, if there is, I am sorry for reposting. I was asked to explain a table from an ANCOVA , specifically the values of F, etc. The table in question is Table 1. Can anyone help? A.
5. ### Fixing behavioural difference of demographics

Currently collecting employment/working satisfaction data from survey at different countries. Same set of questions is used. I have come across that people from some countries tend to be more optimistic/pessimistic than others. How can I take their answering behaviour into consideration when...
6. ### Method/test to use analyzing survey

What type of analysis to do on staff engagement survey to find root cause of problem? Questions covers trust, well being, working environment topics. Answers collected are in 1-5 scale, 1 being strong agree. Method used so far is finding correlation between the questions. Any other...

Part I. Chi-Square Goodness of Fit Test (equal frequencies) A random sample of 118 weights of teenagers is obtained and the last digit is recorded. The frequency of each digit is recorded in the following table. If people report their weight, they tend to round. Test the claim that the...
8. ### What test to use in SPSS....PLS HELP :((

Hi, I'm trying to write my dissertation for my 3rd year undergrad project and I am really stuck with the stats :( I carried out an observational study using questionnaires looking at public knowledge of dementia. I specifically want to look at how knowledge of Alzheimer's Disease (AD) and...
9. ### Anyone can help me with choosing classes?

I am a sophomore in UT Austin. Our university does not have statistics degree for undergrads so I am here for help :( I am interested in applying for statistics grad school in the future, especially in OR, Machine Learning. This year I've taken probability. Any courses may help me solid the...

11. ### drawing up a mediation model with 2 predictors and 1 mediator

Hello all, I was hoping someone could help my understand where a certain value comes from in my data output (using SPSS). I have performed a hierarchical multiple linear regression and the used PROCESS to find that my model has 2 predictor variables which both go through the 1 mediator variable...
12. ### Generalized linear mixed model: Type III significant but multiple comparisons not significant

Hi guys I am running a glmm model for my data, the Type III tests of fixed effects is showing that there is a significant effect of treatment but when i run the multiple comparisons, non of the treatment levels are significant. What causes this confusion? Is my model not right maybe? Regards...
13. ### How to show statistical equivalence between groups of data?

I'm trying to determine if these two groups of data are equivalent. How do I show that mathematically? I have conducted an experiment in which three samples were each measured at two time points as shown in the image. I would like to compare these data and demonstrate (with some sort of...
14. ### "Number of Persons” Vs “Number of Person-years” in a Stationary Population

I have learnt that the life table function nLx is the number of "person-years" lived by the cohort between ages x and x+n. But for stationary population, nLx is defined as the number of persons in the population who at any moment are living within the age interval (x, x+n). I don't...
15. ### Help with choosing a method

Hi, I am currently conducting a short research paper for my university course and am struggling to determine which statistical analysis would be appropriate for the data I have collected. I surveyed two groups of 50 people: 50 x people aged 40 and over 50 x people aged under 40 My hypothesis...
16. ### Standardising a score of values

Hello, I am working on developing on a standardised score from a number of scores. The values will be ranging from large to small of each score and I am trying to develop a way of proportionally measuring different data sets. I have something at the moment which is: (x1/largest x in dataset1)...
17. ### Sum of two normal distributions

Hello, I'm doing data analysis research and currently I'm trying to fit the simple model to a data sample. From physical speculations I know that the distribution should be a sum of two normal distributions with different parameters (mean, width, area). I fitted my data with the model and it...
18. ### Sampling Distribution Problem

Roll a dice five times. Record the results in Sample 1. Repeat the experiment for Sample 2, 3, and 4. In a live classroom setting, actual survey data is used. In this knowledge check online environment, please use the following data: Sample 1 Sample 2 Sample 3 Sample 4 2 4...
19. ### Analysis for difference in variances between group?

I have data for 100 different biomarkers. Each biomarker has data for 4 groups (A,B,C,D) with ~2000 observations in each group. I've read a lot about ANOVA but I'm not looking for a difference in means, only a difference in variances between the 4 groups, for each biomarker. I know there is the...
20. ### Which Statistical test is it?

Any chance anyone knows the answer to this? I know it's not paired t-test but don't know which of the others it is A hotel manager would like to test whether the average time taken for customers to complete the hotel's online booking form is less than 5 minutes. She selects a sample of 40...